FR2587681A3 - LONGITUDINAL WELDING APPARATUS IN A PACKAGING MACHINE - Google Patents

Abstract

Longitudinal welding equipment in a machine for packaging products fed on a conveyor belt inside a continuous film of plastic material wrapped around said products with overlapping longitudinal side edges, comprising a longitudinal welding means positioned above said edges on means generating an oscillatory rotary-­translational motion on a vertical plane, furthermore provided being at least one pressure and accompanying belt atop said products wrapped inside said film, said welding means and said pressure belt being operatively driven by a same central motor means which actuates said conveyor belt, said welding means being equipped with means for temperature control operatively connected to the packaging speed.

Description

i "Longitudinal welding machine in a packaging machine"

  The present invention relates to an apparatus for

  longitudinal tread in a packaging machine.

  In food packaging machines taken one by one using

  continuous films of plastic film, heat shrink-

  tables or not, wrapping the products, we know how to weld

  said film film, wrapping the product, transmitting

  towards the direction of the advance of the products or the film, so as to carry out a packaging

closed, at least partially.

  Indeed, it is noted that the superimposed longitudinal edges of said film still remain free and it is always possible, in one way or another,

  to intervene on the packaging or to alter it. -

  In view of the above, it is interesting to practice welding on the superimposed edges so as to completely close the packaging and prohibit

  any violation of the product contained within the film.

  This last longitudinal welding operation involves a new manipulation of the packaging

  transversely welded, which increases the cost of

  and sometimes requires a new operator

  to perform this last operation.

  The main object of the present invention is to provide an apparatus for longitudinal welding of

  edges of film placed on the products for the enve-

  lopper, able to operate continuously, automatically

  and synchronized with the operation of the packaging machine, thereby avoiding a last

external intervention.

  According to the invention, this and other objects are attained by the production of an apparatus for longitudinal welding in a packaging machine.

  food products, over a transport band

  in a continuous film of plastic

  folded on products with long side edges

  superimposed diners. According to the invention, this apparatus comprises a longitudinal welding system disposed above the longitudinal edges to be welded, on a support assembly animated oscillating movements of rotation and translation in a vertical plane, while it is provided, furthermore , at least one upper band of pressure and coupling for

  products packaged in the film, the system of

  the pressure band being moved by the same central motor as that which drives the conveyor belt and

  the welding system being provided with regulating systems

  temperature, the function of which is function

the speed of conditioning.

  The structural and functional features and advantages of the apparatus according to the present invention

  will be better understood by the following description given in

  As a non-limitative example, with reference to the sketch

annexed in which:

  Figure 1 is a schematic side view of the

  according to the invention; Figure 2 is a partial plan view of the apparatus shown in Figure 1; Figure 3 shows the electrical diagram of the welding apparatus according to the invention; Figure 4 is a graph giving examples of the variation of the welding temperature as a function of the

packaging speed.

  With reference to FIGS. 1 and 2, a side 10 of a packaging machine supports a longitudinal welding apparatus according to the present invention indicated in its

together by 11.

  The packaging machine comprises essential-

  a conveyor belt 13 for a series of products

  14 these products being supplied to the courtroom.

  by pushing systems schematized in 12.

  A central motor-drive 15 operates, using

  of a belt transmission 16, another variator inter-

  17 which, by a chain transmission 18,

  cascading, drives a motor roller 19, around

  from which the conveyor belt 13 is guided.

  In correspondence of the feeding zone of the pro-

  14 is disposed a return roller 20 of the strip

  13 to which is guided a film of plastic material

  21 that takes place from a reel 22 and interferes with

  laying between the conveyor belt 13 and the products 14 to be packaged. According to a known method, the continuous film 21 is rolled entirely on the products 14, the lateral edges

  longitudinal lines being superimposed, before reaching the

  longitudinal welding wire 11 and to a welding device

  transverse step schematically represented by 9.

  The apparatus 11 comprises a pair of lateral shoulders

  23 support rails which are arranged above the side 10

  of the frame, which can be moved vertically

  tioning by means of a small pressure wheel 24 according to the thickness variations of the products 14, so as to put in contact with the products an endless band

  superior pressure and accompaniment 25.

  The pressure band 25 is carried by at least one pair of end rollers 26 whose bearings are carried by the pair of shoulders 23 and which are provided, laterally, with pinions 27 wedged onto their shafts and

  operated by a chain transmission 28.

  A gear wheel 29 drives the chain transmission 27; it is linked in rotation to a second gear 3C whose diameter and the number of teeth are different

  and which is driven by a chain transmission 31.

  A pair of toothed wheels 32 and 33, whose number of teeth is different, are keyed on the shaft of the motor roller 19, the first being connected to the chain transmission 18 coming from the intermediate variator 17, and the

  second to the chain transmission 31 actuating the

longitudinal welding wire 11.

  This last chain transmission 31 has a tensioning lever 34, hinged at 37 with respect to the side 10

  of the frame and kept in an active position by an elastic element

  or spring 35, the lever carrying, at its free end, a small idler gear 36, mounted on a journal.

  The lateral shoulders 23 support, mounted pivotally

  in the center of a shaft 38, a right-angle lever 39 whose upper end is articulated, at 40, on a rod

  41 of adjustable length, by a cylinder 42 itself

  abutted on the shoulders 23, and whose other end

  door, articulated at 43, a longitudinal welding device

  Nal 44, oscillating type, with welding body of circular shape.

  for example, in the form of an edge, arranged in the

  same direction of movement as the products and

  tible to achieve a continuous weld 58.

  e-body-of the welding device 44 rests on a complex support assembly comprising a rocker 45, a connecting rod 46 whose free end is articulated on the crank pin 47 of a pinion 48, whose rotation shaft 49 is worn by at least one shoulder 23. The rotation of the pinion 48 is controlled by the same chain transmission 28 which

actuates the pressure band 25.

  The pinion 48, as well as the connecting rod 46 and the balance, constitute the articulated quadrilateral which transforms the continuous rotary movement of the crank pin 47 into alternating oscillating movement of the balance 45 and the device

  longitudinal welder 44 which is integral.

  The equilibrium lever 39 and the cylinder 43 constitute the device which raises and lowers the longitudinal welding device 44 at each start-up.

  or stopping the packaging machine.

  The use of a longitudinal welding device

  Practically continuous operation requires

  appropriate regulation of the welding temperature, which must be a function not only of the

  welding but also variations in the speed of con-

  ditionnement. For this purpose, a regulating element 50, for example a voltage regulator (FIG. 3), has been provided, which is suitably mounted at the time of switching on.

  the packaging machine so as to have a cer-

  This is achieved, for example, by the use of a first microswitch 52 actuated by a plate 53 connected to a dispensing spool 54 actuated by the electrodes.

  speed variations of the central motor-drive 15.

  Indeed, hardly does the speed exceed a first

  the first predetermined value (FIG.

  tribution 54 is actuated and moves, thus causing,

  through plate 53, the commitment not only

  first microswitch 52, but also a second microswitch 55 with switching input

on the transformer 51.

  This switching involves a growing level of

  voltage (Figure 4) and, consequently, a relative increase

  temperature distribution of the welding device 44,

  compensate for larger calorie withdrawals

  tants that the welding body undergoes on a larger number

  of products 14 being packaged.

  We have the same effect of further temperature increase by a third microswitch 56 which is

  switched on when the packaging machine approaches

  maximum working speeds.

  Similarly, the various microswitches are triggered

  when the speed of conditioning the machine

  decreases, thus providing means of regulating the tempera-

  temperature according to the variations of the speed.

  If, for example, the central motor-drive 15

  takes a linear controller as a pump, the movement of the distribution valve 54 controlled by a solenoid valve 57 not only varies the flow rate of the

  pump, but still engages the different micro-inter-

  temperature control switches of the welding device.

Claims (5)

- CLAIMS -   1.- Longitudinal welding apparatus on a food packaging machine (14) equipped with a conveyor belt (13) for a continuous film of plastic material (21) wrapping the products   (14), with longitudinal lateral edges superimposed,   characterized in that it comprises a longitudinal welding device   tudinal (11) disposed above the longitudinal edges to be welded on an animated set of oscillating movements of rotation and translation in a vertical plane with,   Moreover, at least one higher band of pressure and ac-   companion (25) for the products (14) packaged in the film (21), the welding device and the pressure band (25) being actuated by the same central motor (15) as that which drives the conveyor belt (13) , and   the welding device being provided with control systems   the temperature in relation to the speed of the con-   ditionnement. 2. Welding apparatus according to claim 1, characterized in that the welding system has a   circular welding body (44) arranged in the direction of   the products (14), the body (44) being pivotally mounted   so much and its movement oscillating on the side edges   superimposed being controlled by a balancing support assembly   (39) and connecting rod (46), the connecting rod (46) being itself   articulated on a pinion assembly (48) - crankpin (47)   at least one lateral shoulder (23) and set in motion.   transmission (31,33) connected to the central engine tral (15).   3. Welding apparatus according to claim 2,   characterized in that the welding body (44) is pivotally mounted   at the end of a right-angle lever (39), at least one shoulder (23) bearing the central hinge axis of the right-angle lever (39) whose other end is hinged at the end of the rod (41) of a drive cylinder (42) so as to realize a movement of   translation of the welding body (44) in the vertical plane.   4. Welding apparatus according to claim 1, characterized in that the control systems of the   temperature are composed of a pre-   set (50) connected to the welding system (44) via   of a transformer (51), while there is provided a series of microswitches (52,55,56) actuated one after the other when the conditioning speed varies and likely to switch the input / output voltage of the transformer (51) itself.   5. Welding apparatus according to claim 4, characterized in that the microswitches (52, 55, 56) are actuated by a control (53, 54, 57) driven by the central motor (15).